We use Optical Character Recognition (OCR) during our scanning and processing workflow to make the content of each page searchable. You can view the automatically generated text below as well as copy and paste individual pieces of text to quote in your own work.
Text recognition is never 100% accurate. Many parts of the scanned page may not be reflected in the OCR text output, including: images, page layout, certain fonts or handwriting.
1950 FLASHLIGHTING EQUIPMENT 303
continuous and consists mainly of yellow, green and blue lines superimposed on a relatively weak continuous spectrum. Owing particularly to the deficiency in red content this light source produces a distorted rendering of colors but a considerable improvement in the color rendering can be obtained by the addition of cadmium in the discharge.9 The discharge in cadmium vapor produces a powerful red line in the spectrum, while the gaps in the blue-green region of the mercury spectrum are filled by additional lines, so that the color of the radiation is better balanced. The color rendering also improves with increased current density in the arc so that the higher the wattage of the lamp the better is the color rendering. This improvement is due partly to broadening of the lines and partly to an increase in the amount of continuum at the higher current density. Spectral distribution diagrams of the mercury cadmium lamp operating at 1 kw and at 10 kw are shown in Fig. 2. These diagrams show that gaps still remain in the spectrum, but in spite of these gaps practical tests have shown that mercury cadmium compact-source lamps operating at powers above 2.5 kw give a satisfactory rendering of color with Kodachrome Daylight and similar emulsions.
ClNEPHOTOGRAPHY ILLUMINATOR
A portable equipment using the principle of flashing a compact source lamp has been designed specifically to meet the illumination requirements of the high-speed cinephotographer. One equipment, known as the M-R 356 Cine Flash, illustrated in Fig. 3, consists of two lamp heads mounted on stands, and a control unit containing the ballast resistance and other components for operating the lamps.
The lamphouse, an interior view of which is shown in Fig. 4, is of a light sheet-metal construction. It contains a compact-source lamp mounted along the axis of a paraboloidal mirror and is fitted with a front diffusing glass. This optical arrangement gives a high light collection efficiency combined with uniform distribution. The mirror is made of metal so that it is robust and not liable to damage during transport of the equipment. By releasing the locking screws at the rear of the lamphouse, the lamp may be removed through the front of the housing for transport. The high-frequency choke required for the impulse striking circuit is mounted behind the mirror in the lamphouse.
The lamp is mounted in a prefocused holder and the focal position is set normally to produce a spot 10 in. in diameter at a distance of 4 ft from the unit with an illumination constant to within =^15% over its area. A fixed rather than variable focus ensures that the light output from the unit is constant so that the photographic exposure